1. Field of the Invention
The present invention relates to mineral filled .alpha.-amino acid polymer composite materials prepared by the polymerization of an .alpha.-amino acid in the presence of inorganic mineral fillers. Said fillers may be optionally surface-modified with a partially hydrolyzed polyoxazoline prior to said polymerization.
2. Description of Pertinent Art
Laible and Hamann (Advances in Colloid and Interface Science, 13, 65-99, 1980) teach the anionic polymerization of N-carboxy-.alpha.-amino acid anhydrides initiated by surface-modified silica. Said modification of the silica involves a multiple step procedure for converting the surface hydroxyl groups of silica to aminophenyl groups which are chemically bound to the silica surface via silicon-carbon bonds. In this procedure, the surface hydroxyl groups of silica are first converted to chlorosilyl groups by chlorination of the silica with thionyl chloride. The chlorinated silica is then phenylated by treatment with phenyllithium in a diethylether solution. The phenyl groups are subsequently nitrated by the use of acetyl nitrate, and the nitrophenyl groups are reduced by treatment with hydrazinium hydrate in ethylene glycol solution, thus creating aminophenyl groups chemically bound to the silica surface by silicon-carbon bonds. The polyamide grafted silicas are said to be useful in the stabilization of colloidal dispersions to flocculation.
Oya, Takahashi and Sunaga (Chem. Abs. 88, 170838p, 1978) describe polymer blends prepared by the polymerization of an .alpha.-amino acid N-carboxyanhydride in a solution of a thermoplastic in a solvent (e.g., polyvinyl chloride in tetrahydrofuran).
Ebihara and Okada (Chem. Abs. 91, 175714s, 1979) teach the use of glycyl styrene resin in methylene chloride at room temperature for buildup of poly(.gamma.-methyl L-glutamate) chains on the resin particle using the amino group of the bound glycine as an initiation or graft site in the presence of .gamma.-methyl L-glutamate N-carboxyanhydride. Subsequently, the poly(.gamma.-methyl L-glutamate) chains are cleaved with hydrofluoric acid (cleaving the .gamma.-methyl ester group) to produce poly(L-glutamic) acid.
Avry et al (Eur. Polymer J., 2, 355, 1966) describe the grafting of poly(.alpha.-amino acid)polymers to polysaccharides utilizing the O.sup.- Na.sup.+ form of the polysaccharide to initiate polymerization of an .alpha.-amino acid N-carboxyanhydride.